Surface drill mining machines are often equipped with masts. Such machines may be used to drill into the ground during the construction or maintenance of roads, railways, building sites, landscapes, wells, mines, or other areas. For example, a surface drill mining machine may be used to drill holes to access subterranean minerals, liquids, or gases or to place explosives in preparation for blasting. Typically, such machines include a chassis which supports an engine, an operator cab, and a mast. The mast may support and include a drill head, a carousel, and pipe segments which transmit torque from the drill head to a drill bit. The mast may guide the drill head. The carousel may carry a supply of the pipe segments. As the hole is drilled and pipe segments descend below ground, the carousel may successively load additional pipe segments into the drill head to extend the reach of the drill bit. Pipe segments and masts may be available in different fixed lengths.
Depending on the drilling application, one particular pipe segment length may be preferable over another depending on the drilling application, the substrate being drilled, regional standard pipe segment lengths, or other economic or availability factors. As the mast supports and includes the pipe segments and the carousel, it must in turn have a length that accommodates the particular pipe segment used in the drilling application. While a long mast may accommodate shorter pipe segment lengths, the extra length of the mast is unnecessarily costly and adds unnecessary weight to the surface drilling machine. Therefore, shorter and therefore lighter and less costly masts are often used in drilling applications which call for shorter pipe segment lengths. Such tailoring of the mast to the drilling application may, however, make the surface drill machine unsuited to a subsequent drilling application once the initial drilling application is complete. Therefore, depending on the subsequent drilling application, a surface drill machine may need to be retrofit with a new appropriate length mast, which may be a costly and time-consuming process. Furthermore, if roadways and/or railways between the surface drilling machine supplier and the worksite have overpasses, tunnels, or other obstructions, a surface drilling machine with a long mast installed may not be able to travel to the worksite. Thus, long masts may need to be installed onto the surface drilling machine chassis at the worksite as opposed to the controlled environment of the supplier, which may also be a time-consuming and costly process. Additionally, the tailoring of mast length to drilling applications increases surface drilling machine manufacturing complexity, dealer inventory, and ordering lead time.
Surface drilling machines with some degree of mast length flexibility are available. Such flexible masts are often arranged with mast sections stacked on top of a foundational mast and fastened together. More specifically, mast sections may have protruding interlocking upper and lower members through which the fasteners are placed and additional rails to guide the drill head. However, these efforts to provide mast length flexibility have been found largely lacking as the additional rails hinder the use of a pipe-loading carousel. One example of an existing strategy for attempting to provide a surface drilling machine with a flexible length mast is shown by Chang in Chinese Patent No. CN202249794U.
It can therefore be seen that improvements in the arrangement of the surface drilling machine mast and associated structures are desired to increase surface drilling machine drilling application flexibility. Furthermore, improvements to the arrangement of the surface drilling machine mast may increase work efficiency and also reduce cost, manufacturing complexity, and manufacturing time.